Apparatuses and methods for aligning bank notes in a transport system usually have means, which move the bank notes to be aligned in a direction deviating from the transport direction of the transport system and direct them against a guiding element, so as to urge an edge of the bank notes, which is parallel to the transport direction, against a guiding element, so that the bank note has a desired alignment. Usually, for this purpose rollers are used, which are moved by a motor and disposed in the transport system in such a way, that they propel bank notes transported by the transport system in a direction oblique to the transport direction, so as to urge them against the guiding element. Here the rollers act on the bank note, which is transported past, along its entire length or across its entire width. As a result of this there is the possibility that the bank note is deformed, for example folded, when it is urged against the guiding element. This also leads to the fact, that the actual goal, namely aligning the bank note in a desired alignment is not achieved, because the alignment effected by the rollers deviates from the desired alignment.
For improving this problem EP 1 188 699 A2 proposes to use rollers, which are disposed in the transport system and act on the entire length or width of the transported bank notes, the rollers being disposed on a framework, which is adapted to be adjusted by a motor. Furthermore, the prior art apparatus has a sensor unit, which is located in the transport system in front of the rollers and determines the alignment of the bank notes each transported past the sensor unit. Dependent on the determined alignment of the bank note, the rollers or the framework supporting the rollers are adjusted by the motor in such a way, that the movement of the bank note effected by the rollers is dimensioned in such a way, that the bank note, after having completely traversed the rollers, has the desired alignment.
The prior art apparatus therefore has the disadvantage, that the influence of the rollers required for aligning the bank note is determined without taking into consideration the properties of the bank note, which potentially may influence the aligning. Dependent on the state of the bank note, its friction may vary. Very dirty bank notes or limp bank notes normally have a higher friction, whereas new or freshly printed bank notes have less friction. Similarly, the friction coefficient of the rollers may vary, namely when the rollers have been soiled during the operation. These factors in general have the effect, that when aligning by means of the rollers used in the prior art apparatus, the desired alignment is not achieved, because e.g. due to the fluctuations in friction occurring during the operation the desired alignment cannot be achieved to a precise degree. In addition it is a problem, that the rollers act on the transported bank note along its entire length and across its entire width. In particular with bank notes, which exhibit a damage, such as tears or the like, it can occur, that due to the force exerted by the rollers the already damaged bank note is further damaged or definitely destroyed.